The brutality of foreign occupation did not strangle the will to resist. Intermittent, spontaneous acts of resistance during the summer of 1941 led eventually to the formation of a more united effort. In September, the National Liberation Front (Ethnikon Apeleftherotikon Metopon--EAM) was formed to coordinate resistance activities. A secondary aim of the organization was to ensure free choice of the form of government that would follow liberation.

In the five-part coalition of EAM, the old constitutional disputes between monarchists and republicans resurfaced, providing the KKE an opportunity to dominate the organization from its inception. The KKE also took a dominant position in subordinate organizations, such as the combat arm of EAM, the National People's Liberation Army (Ethnikos Laikos Apeleftherotikos Stratos--ELAS). The KKE's position was possible for a number of reasons. First, in the 1930s the Metaxas regime had driven the communists into precisely the type of underground resistance activity needed to fight the Nazis. Unlike traditional Greek parties (including its allies in the EAM), the KKE was a close-knit, well-organized group with a definite ideology. Also, the communists projected a vision of a better future at a time of great suffering, appealing especially to people who had lacked privileges in Greece's traditional oligarchical society. Finally, the firm stand of the Greek communists on native soil compared well with the actions of the old politicians and the king who had fled to the safety of London and Cairo.

Thus, although the vast majority of EAM and ELAS members were not communists, most were ready to follow the communist leadership. Other resistance groups, such as the National Republican Greek League (Ethnikos Dimokratikos Ellinikos Stratos--EDES), existed, but EAM and ELAS played the largest role in resistance activities. Monarchist elements of society generally withheld support from resistance groups.

Little coordination occurred between the government-in-exile and resistance forces in occupied Greece. Some exile groups even counseled against resistance movements because of the brutal reprisals threatened by the occupiers against the civilian population. In fact, in 1942 the escalation of sabotage, strikes, and mutinies by resistance groups did increase the severity of reprisals. The Germans decreed that fifty Greeks be killed for every German soldier lost, and entire villages were destroyed. The puppet occupation government formed security battalions manned by collaborators, many of whom were die-hard monarchists and thus opposed to the resistance movements because of old constitutional issues. Removed from such terrors at home, the government-in-exile rapidly lost legitimacy.

One of the war's many tragedies was the destruction of the Greek Jewish population. Before the war, Athens, Ioannina, and Thessaloniki had vibrant and sizeable Jewish communities. From Thessaloniki alone, 47,000 Jews were sent to Auschwitz, and by the end of the war Greece had lost 87 percent of its Jewish population.

Under the leadership of Athanasios Klaras, who took the nom de guerre Ares Veloukhiotis, ELAS carried out a number of successful sabotage missions beginning in mid-1942. The British special operations forces provided arms and experts, who together with fighters from ELAS and EDES struck a major blow against Germany by destroying the railroad line between Thessaloniki and Athens where it spanned the Gorgopotamos Gorge in central Greece. This action severed a vital supply line from Germany to Nazi forces in North Africa. But Britain failed to achieve long-term coordination of Greek resistance activities with conventional operations and other resistance groups in the eastern Mediterranean because of Prime Minister Winston Churchill's steadfast support for the Greek monarchy. By the end of 1942, Greek resistance activity was distracted by internal conflict over the eventual postwar direction of national government. ELAS began a second campaign, this one aimed at ensuring communist domination of resistance activity.